Birds in Chicago laying eggs earlier due to climate change, research suggests

New research released Friday shows Chicago area birds are changing their nesting habits, and it's connected to the climate crisis.

Inside the Field Museum, John Bates uses the old egg collection to tackle new problems, like this.

"A lot of people think of museums as old places with old dusty data. And that's not really true. We're always looking for modern uses of things," said John Bates, curator of birds at the Field Museum and the study’s lead author.

He turned to eggs preserved in the Field Museum more than a hundred years ago. There are 40 to 50,000 eggs in a cramped room, including some that date back to the 1870's.

Bates and a team of researchers compared the old data to that of eggs collected recently.  

They discovered about a third of Chicago area birds lay eggs on average 25 days earlier than they did a century ago.

"These birds shifting their breeding dates a month earlier is a really significant change in their biology," said Bates.


Their research also shows the change in egg laying corresponds with climate change. More research is needed, but Bates says one crucial thing is clear.

"Climate change is happening, and also that we can do something about it."

Bates showed us Peregrine Falcon eggs. 

Decades ago, studying their thinning and cracking eggs helped illustrate the dangers of DDT and get it banned. He’s hopeful more studies will spur change for other environmental problems.

"Our goal is to make them available, and we know from experience they’ll be used in ways we’re not even thinking of yet," said Bates. "This is why museums exist, to get this material in here, to be here hundreds of years from now to help researchers understand what’s going on."

And maybe they'll crack other key questions about our changing world.